A widget bodgery thread, aka "I am the great Cornholio, I need through-pass for my bung-hole!" (Sorry.)

Dynamo hub - I have a charge box and rear light wires exiting steerer via a modified top cap, using a grooved/filed out bung to tension top cap and open up access to the steerer when needed -



The challenge is the steerer bung or star nut replacement. Currently I use a filed-out carbon steerer bung but tensioning it down gradually collapses the top section out-of-round, since there's a groove in the side edge large enough for 2 coax wires. It works but it's not long-term reliable.

I've thought of installing a star nut around a perma-fit wire with quick-connect ends, but I know one day I'll regret losing that easy access to the full open steerer. There are BMX / DJ caps with hollow bolts for gyro or brake hose and bar spins but they don't work. A long headlock type of device would work (no star nut needed, top + bottom contact only) but it's weighty and a bit OTT, also has other issues if my front guard is fitted to the bolt eyelet under the crown.

What I need is some kind of 3-point contact steerer bung. Easy... ha. Any flashes of genius out there?

Nice work! I'll have a look, I think I have a cut out compression bung somewhere in the shed.

I'm guessing the hole in a 'vented' bolt/screw isn't big enough?

https://www.accu.co.uk/en/vented-screws ... V-M5-12-A4

Is the steerer alloy? Do you have spacers under the stem?

You get what I'm thinking about...

Also this is a handy little fellow
https://www.extremtextil.de/kabel-durch ... tomer.html
Can be easily retrofitted.

I have a slotted bung which came with a top cap charger, mine is a cinq5 I’m sure you can get replacements. One of these might do the job
https://m.ebay.ie/itm/Acor-CNC-Alloy-He ... iid%253A13


Here’s the cinq5 version

https://www.sjscycles.co.uk/dynamos/cin ... ander-nut/

I had the cinq5 on my shand it seemed to work very well

Here's my slightly parallel thought.

You only need the star nut / headlock to preload the headset. I've never had to adjust one of these on a ride (other than perhaps just after installing a new headset etc. as everything settles in). In my XC race days I'd often not even bother with it.

With that in mind, you'll have a free steerer tube, and can then just use a plastic top cap to neaten it up / hold the cable. Many plastic caps here: http://www.essentracomponents.com/en-gb/caps-plugs

Looking at your pic James, it seems the wire exits the steerer tube and goes into a top tube bag. I realise that in the normal course of riding that the bars only make small movements but I'd be worried about pulling the whole thing out if the bars swung round inadvertantly. With my gravel bike setup, I have a Juice cube attached to a Kemo switch-rectifier gizmo together with all the usb and revo leads in a little bag which fits under my stem so the whole thing including the gps and light moves with the bars. Obviously not as easy if you are using a bigger powerbank or switch arrangement.
I seem to remember that there was a very neat solution being sold by a german guy which had everything in a heatshrink tube which slid down the steerer tube, it wasn't cheap but looked very well put together, only issue was you needed a fairly long tube to fit everything in. Unhelpfully I can’t remember his name,sorry.

I have come to the conclusion that wires routed outside the head tube is a more reliable and easier trail side repair than trying to neaten it all up running it inside. Filed out bungs, star nuts with wires through, etc is a fiddly thing to make and even more fiddly to repair (if you can find the broken or chafed wire in the dark)

I'm guessing the hole in a 'vented' bolt/screw isn't big enough?

No, unf. But a larger version may be, generally the issue is getting the block connectors in and out.

Is the steerer alloy? Do you have spacers under the stem?

You get what I'm thinking about...

Steel. Grooving the top of the steerer? Had thought about that but the grooved spacer on top of the stem does the same job for the less committed!

cinq5

we have a winner, thanks. Not seen that - it's exactly what my filed out carbon steerer bung is, just (I expect) more durable. Ordered.

Looking at your pic James, it seems the wire exits the steerer tube and goes into a top tube bag. I realise that in the normal course of riding that the bars only make small movements but I'd be worried about pulling the whole thing out if the bars swung round inadvertantly. With my gravel bike setup, I have a Juice cube attached to a Kemo switch-rectifier gizmo together with all the usb and revo leads in a little bag which fits under my stem so the whole thing including the gps and light moves with the bars. Obviously not as easy if you are using a bigger powerbank or switch arrangement.
I seem to remember that there was a very neat solution being sold by a german guy which had everything in a heatshrink tube which slid down the steerer tube, it wasn't cheap but looked very well put together, only issue was you needed a fairly long tube to fit everything in. Unhelpfully I can’t remember his name,sorry.

Drop bars - they don't swing more than about 50 degrees. I have a small phone pouch here that I was going to adapt so it can go under the stem, stems only 50-70mm but it does reduce that wire movement as you say, also frees up my gastank to hold more food. That's very important : )

I've never had to adjust one of these on a ride (other than perhaps just after installing a new headset etc. as everything settles in). In my XC race days I'd often not even bother with it.

Fair point .. makes me a bit nervous though. Adjusting bar height mid trip maybe. Or if the stem should move ie in a crash, w/o the comression nut you might have a faff on your hands.
Those plastic caps could be handy though, thanks - spokes up the seatpost, etc.

I have come to the conclusion that wires routed outside the head tube is a more reliable and easier trail side repair than trying to neaten it all up running it inside. Filed out bungs, star nuts with wires through, etc is a fiddly thing to make and even more fiddly to repair (if you can find the broken or chafed wire in the dark)

I have wondered about doing it all externally, the internal route keeps much of the weather off it though. Less to snag. Once soldered and sealed properly and with the right bung giving easy access it's reliable ime. It's all wrapped and there's no place for it to chafe, well no more than any wire route that needs securing along the way. I use a sleeve outer over vunerable spots so keeping an eye on that prevents any damage to the coax.

Thanks for all the ideas, very useful. As ever, if you need it, someone's probably already made it

jameso wrote:Steel. Grooving the top of the steerer? Had thought about that but the grooved spacer on top of the stem does the same job for the less committed!

Drilling a hole through the steerer beneath the Stem was my idea. I'm certain a steel steerer would hold up just fine with such a hack.

Also, if you're worried about damaging the cables, some hot glue and/or moto foam can help keeping things rattle free and thus prevent rubbing on rough tracks.

Drilling steerers .. it may hold up long enough but I wouldn't trust it unless it was designed for that in the first place.

Sugru is also very useful for protecting cables

jameso wrote:Drilling steerers .. it may hold up long enough but I wouldn't trust it unless it was designed for that in the first place.

You'll be fine above the stem. You'll probably be ok just below the stem. I wouldn't trust it anywhere near the crown.